As a consequence of industrial gas refining operations, oil distillation and ore refining operations, an aqueous stream containing large quantities of sulfur is generated. Existing environmental, as well as economic, considerations dictate that the sulfur be removed so as to either recycle the aqueous medium, minimize the amount of sulfur discharged into the atmosphere or recover the sulfur for commercial use. A number of processes for the removal of sulfur from an aqueous medium by melting and separation have been reported.
In U.S. Pat. No. 4,158,039, there is disclosed a pressure vessel for separating sulfur from an aqueous suspension wherein the vessel is divided into an upper portion containing a heating and stirring device and a lower portion which serves as a settling chamber.
In U.S. Pat. No. 4,206,181, there is disclosed a pressure relief vessel wherein the separation process in the outer annular chamber is increased without actually increasing the diameter of the chamber by providing a ring of inclined separator plates within the outer annular chamber.
An ore refining process wherein sulfur coalescence is achieved by passing the ore suspension first through a funnel to bring the sulfur prills closer together and then through a single passage screen to coalesce the sulfur prills is disclosed in U.S. Pat. No. 3,649,217.
A continuous filter apparatus for removing sulfur from an aqueous suspension is disclosed in U.S. Pat. No. 2,731,332.
Similarly, the use of a porous filter bed to remove sulfur from sulfur-containing ore is disclosed in U.S. Pat. No. 3,689,226.
The problem with the above processes is that they do not remove very small sulfur particles with colloidal properties.